Sit on the edge of a bench with your feet flat on the floor, knees bent 90 degrees. Grasp the seat on either side of your butt; make sure your fingers are facing forward. Walk your feet out slightly and inch yourself off the seat. (A) Bend your arms, keeping your elbows pointed straight back as you dip your butt toward the ground. Simultaneously contract your abs and pull your right knee toward your chest. (B) Return to start. Concentrate on using your arms to raise your body, rather than pushing up with your legs. Complete a set, alternating legs. 10 to 12 reps
Make the move more challenging by performing it with your legs extended.